The present invention relates generally to steps for climbing hollow poles, such as utility poles, and similar structures and, more particularly, to a step assembly that readily attaches and detaches a step to and from such structures.
Elongated poles are commonly used to maintain items above and over the ground for numerous reasons, including safety and ground space conservation purposes. The utility industry, for example, uses many poles to support cables and other components of the utility""s system. These poles are often hollow and made of steel and/or fiberglass. These poles are typically fitted with steps that extend radially from the pole in a cantilever fashion to enable utility personnel to climb the pole to perform maintenance operations on the equipment. The specific structures of these pole steps vary.
For example, one known pole step is disclosed in U.S. Pat. No. 5,941,485 to Davidson et al. This pole step includes a mounting subassembly and a separate step. A shortcoming with this design is the potential for the step to become unintentionally detached from the pole. For example, the step is mounted using a vertical slot which slides over the head of a mounting bolt and a washer at the head. Other then the clamping pressure of the bolt, the step is not locked against rotational and upward movement, especially if the bolt is not tightened adequately or becomes loosened from use. Further, when the climber accidentally hits the bottom of the step with his or her foot, there is potential for the step to loosen and unintentionally disengage from the mounting subassembly.
Another known utility pole step is one that uses a mounting plate, a washer and a nut to attach an elongated step in a cantilever fashion to the pole. The elongated step includes an arm portion at one end that is bent 90-degrees with respect to the rest of the step. The step extends through the bore into the utility pole to position the arm in the pole to engage the inner wall of the pole. A portion of the step material at the bend creating the arm is pinched to create a projection. The step also extends through a hole in the mounting plate at the exterior of the pole. The bottom of the hole in the mounting plate includes a tab angled away from the plate into the hole to engage the pinched projection of the step bend to prevent the step from being rotated as the nut and lock washer are being tightened on a threaded portion of the step to secure the step.
A shortcoming of this design is its failure to ensure that the step cannot rotate about its longitudinal axis upon torque created by a user""s foot rubbing across the step. The projection engagement only limits rotation in one direction. Further, upon enough rotation in the direction away from the bend projection, the arm has the potential to face sideways or even downward which may result in the step becoming loose and even detached from the pole. Another shortcoming includes the potential weakening of the step caused by the pinching of the material at the bend, requiring strength to support the step in the cantilevered fashion from the pole. A shortcoming to both the foregoing designs is that the components are not part of a common assembly by sufficiently captivating the components to facilitate effective and efficient installation, especially as one is climbing the pole. For example, the Davidson design has two separate parts requiring separate installations. The mounting subassembly must first be attached to the pole in order to later attach the step. With the other design, the components, such as the mounting plate, can easily come off the elongated step. It is common for a climber to have to install the steps as he or she climbs the pole because the lower portion of the pole has the steps removed to prevent unauthorized climbing of the pole. Thus, this design is problematic especially when the climber is installing the steps as he or she climbs the pole because, not only does the climber have to be concerned with properly tightening the assembly, with a tool, he or she has to deal with the multiple components and their easy potential to become separated from the assembly.
Thus, there remains a need for a pole step assembly that secures the step against unintentional rotational movement and that facilitates efficient and effective installation to the pole.
The present invention pertains to a step assembly that is capable of securing to a hollow pole having at least one hole for mounting purposes. The step assembly includes an elongated step with a first end portion and a second end portion opposite the first end portion. The first end portion has an arm and at least one flat. The first end portion is capable of extending through a hole to position the arm inside the hollow pole.
The step assembly also includes a bushing on the step. The bushing defines an interior hole with at least one interior flat for engaging the flat of the first end portion to prevent relative rotational movement between the step and the bushing. The bushing also includes at least one exterior flat.
The step assembly further includes a base on the step. The base includes a surface for engaging the hollow pole to prevent relative rotational movement between the hollow pole and the base. The base also includes an edge defining a hole for receiving the bushing and for engaging the exterior flat of the bushing to prevent relative rotational movement between the bushing and the base.
The step assembly further includes a clamp along the step. The clamp has surfaces that engage the step at various predetermined positions to prevent longitudinal movement of the bushing and base along the step.
The second end portion of the step may include a stop such that the stop and the arm of the first end portion are of sufficient size and configuration to sufficiently captivate the bushing, the base and the clamp on the step to facilitate securing of the step assembly to the hollow pole. The base may include one sidewall, which includes the surface engaging the hollow pole. The sidewall also spaces the edge defining the hole of the base from the hollow pole. The surface engaging the hollow pole may have an arcuate profile to complement an arcuate exterior profile of the hollow hole.
The first end portion of the step may have at least four flats. The interior hole of the bushing may be defined, at least in part, by at least four flats. Thus, the four flats of the step would engage the four flats of the bushing to prevent relative rotational movement between the step and the bushing. The first end portion may further have a square cross-section forming at least four flats of the step. The interior hole of the bushing also may have a complementary square cross-section defined by the at least four flats of the bushing.
At lease some portion of the first end portion of the step may have a larger transverse cross-section than that for the remainder of the step. The bushing and the base may encircle the step. The bushing and the base also may be permanently affixed to one another or, alternatively, may be formed to constitute a single component.